Growing urgency over Syria American warships being repositioned but what is coming next. President Obama in a rare White House meeting with his national security advisors today and this is what prompted the meeting. Growing proof that chemical weapons might have been used to kill more than a thousand in Syria among them so many children. Tonight volunteers Doctors Without Borders inside Syria treating patients. Now revealing the symptoms they're treating -- more than 3000 patients were question with what they called neuro toxin symptoms similar to what you've seen -- chemical attack. Within 300 people they say died. Tonight here three urgent questions is America about to get involved what are the options if so how soon. ABC's chief global affairs correspondent Martha Raddatz reports from the region tonight on the crisis in Syria Martha. Good evening David as we stand here tonight. US warships are being repositioned very nearby in case -- the military air strike on Syria. Tonight evidence of a chemical attack in Syria is -- new images showing the horror. The president spent the day huddled behind closed doors with his national security team. Weighing the evidence and his military options were still gathering information about this particular -- but it is very troublesome for a Monday. The table targeting Syrian military -- government buildings with cruise missiles. Four navy warships are already in the Mediterranean. Loaded with tomahawk missiles. US fighter jets could also attacked firing from outside Syrian airspace so pilots would be out of harm's way. The administration's been very forthcoming in saying. That risk must be low we cannot risk getting servicemen and women hurt and we don't wanna get pulled into another quagmire Middle -- Nothing will happen until the US confirms the chemical attack. And in an -- to me is that the will be all today Syrian state TV claims the rebels were behind the attack. Abandoning the position that no chemical attack occurred. UN officials and Syria are pushing for access to the site for inspections. The group Doctors Without Borders said today that. 3600. Patients with -- toxic symptoms were treated the day of the suspected attack. They say 355. -- those patients died. David the president has been very reluctant to intervene in theory about what these urgent meetings and his strong language. It suggests he may be changing his mind.

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